It is known that sand aggregates used in making construction materials such as concrete can contain clay materials that are detrimental to the concrete and/or to the efficiency of plasticizers used in the concrete.
For example, U.S. Pat. Nos. 6,352,952 and 6,670,415, owned by the common assignee hereof, Jardine et al. disclosed that certain clays, which expanded when in contact with water, were responsible for adversely affecting the dosage efficiency of “EO/PO” type superplastizicers (e.g., which contained ethylene oxide and propylene oxide groups). Jardine et al. taught that clay-activity-modifying agents, such as organic cations (such as quaternary amines which have a strong affinity for cationic exchange with clay), could be introduced to the clay before, during, or after water is introduced to the clay.
As another example, in U.S. Ser. No. 11,575,612 (Publ. No. 2007/0287794 A1) and U.S. Ser. No. 1111/575,607 (Publ. No. 2008/0060556 A1), Jacquet et al. disclosed compositions and methods for inerting clays in sand aggregates intended for use in preparing concrete. The compositions could include monomers already containing a cationic quaternary amine functional group: such as diallyldialkyl ammonium, quaternized (meth)acrylates of dialkylaminoalkyl and (meth)acrylamides N-substituted by a quaternized dialkylaminoalkyl. Particularly preferred were cationic polymers obtained by polycondensation of dimethylamine and epichlorohydrin.